Artificial limb



K. C. VESPER Feb. 18, 1947.

ARTIFICIAL LIMB Filed May 1, 1944 3 Sheets-Sheet 2 I Patented Feb. 18, 1947 UNITED STATES ATENT OFFICE. v

\ ARTIFICIAL LIMB Karl C. Vesper, Santa Monica, Calif. Application May 1, 1944, Serial No. 533,503

11 Claims. 1

My invention relates to the artificial limb art and, more particularly, to an artificial arm adapted for use in connection with a forearm stump.

The primary object of my invention is to provide a wearer who has lost a handwith a mechanical device that will serve as a hand or toolholding device to replace, so far as possible, the normal functions of the lost hand.

vMany types of artificial forearms have been developed in the art, but most of them have been unsuccessful due largely to the fact that they have been designed without regard to sound medical and mechanical principles. For example, most of such devices are heavy and cumbersome and rapidly tire the wearer; many of them are difficult, if not impossible, to fit properly; most of them ar improperly ventilated and consequently cause overheating ofthe stump with attendant irritation thereof; and all of them of which I have knowledge put the entire weight of the device upon a small area of the stump, causing chafing and discomfort.

It is therefore an object of my invention to obviate the foregoing deficiencies of the prior art devices by providing an artificial forearm which is light in weight, simple to fit to any stump bya layman without medical knowledge, and which provides suspension of the stump in' a manner consistent with recognized medical and mechanical principles.

For example, my invention enables the artificial forearm to be accurately and simply adjustecl to a length corresponding to the length of the other good arm. It provides a pivoted joint between the upper and forearm portions thereof such that the pivotsof the joint are axially aligned with the normal condyles of the elbow joint of the arm, which exactly simulates a normal arm. Furthermore, my invention provides a well ventilated space in which the stump is supported by a weight-distributing suspension while still permitting free twisting of the stumpfin pronation or supination, and at the same time retaining accurate control by the wearer over movement of the artificial arm to a degree substantially commensurate with that of a normal ar'm. All of these beneficial results are further objects of myinvention. j g

Another object of my invention is tojprovide a stump sheath of novel. form which is adapted to fit a stump so accuratelyv and comfortably that the weight of the fore-arm is distributed over 'a substantialarea of thestump instead of being to provide a novel tool holding device which is adapted'to be secured to the forearm member of an artificial arm and which is adapted to receive and hold a number of diiferent types of tools in substantially any desired position relative to the forearm, to simulate the action of a normal hand. Still another object of the invention is to pro vide an artificial arm having actuating means for operating a standard hook attached thereto so that actuation of the hook will not tend to rotate the artificial forearm relative to the upper arm. This tendency of the forearm to rotate relative to the upper arm has been an objection-q abl defect of prior art artificial arms, and my construction obviates it. 1

Another object of the invention is to provide a manner of securing the stump sheath in the artificial forearm such that the weight of the artificial forearm will be distributed evenly over the forearm and stump. I prefer to accomplish this by securing only the bottom of the stump sheath, along its longitudinal axis, to the artificial forearm. f

Other objects and advantages will be. apparent from the following specification and the drawings, which are for the purpose of illustration only andin which: Fig. l is a plan view of my invention, with a standard form of hook attached thereto.

Fig. 2 is a side elevational view, partly in section, of Fig. 1. Fig. 3 is a bottom view of the device illustrated in Fig. 1.

Fig. 4 is a longitudinal sectional view taken through the novel tool holder of my invenion. Fig. 5 is a plan view of a portion of the device shown in Fig. 4. v Fig. 6 is a side elevational view of the tool holder shown in Fig. 4, having an accessory mounted thereon. p Y Fig. 7 is a sectional-view similar to Fig. 4, but illustrating the device in one of its operational positions with a different type of accessory mounted therein. Fig. 8 is a bottom view of the accessory shown inFig.6.r Fig. 9 is a sectional view taken on the line 99 ofFig.8. n Fig. 10 is a plan view of an accessory adapted to beused with my invention. Referring to Figs. 1 2, and 3 of. thedrawings.

my device includes upper-arm means l2, forearm means l3, and tool holding means M.

The upper-arm means |2 includes an upperarm band l of generally cylindrical form, preferably formed of a pliable material, such as leather, and having a slit opening H3 in the top thereof so that the band may be: slipped onto the upper-arm of the wearer just above the elbow in a position such that the slit opening lies along the upper portion of the upper-arm. Perforations I! are provided in the upper-arm band l5 to assist in ventilating that portion of the upperarm of the wearer enclosed within the arm band, and hooks |8 are provided to receive suitable lacings (not shown) by which the upper-arm band I5 is securely fastened to the upper-arm of the wearer.

Secured to each side of the upper-arm band 5, as by lacings 20, is a pair of rigid straps 2| and 22, preferably formed of a light metal, such as aluminum alloy. As best shOWn in Fig. 3, the inner ends of the straps 2| and 22, respectively, are bowed outwardly at 23 and 24, terminating in flat parallel end portions 25 and 26.

The end portions 25 and E6 of the straps 2| and 22, respectively, are pivotally secured to a plate member 28 by suitable pivots 29 and 30, respectively, the plate member including down wardly and inwardly bowed arm portions 3! and 32, from the lower ends of which forwardly project arms 33 and 34, respectively, formed integrally with the bottom portion 35. The specific design of the straps 2| and 22 and the plate member 28 is important, as it is designed to position the pivots 29 and 38 in alignment with the normal epicondyles of the wearer and to provide the maximum comfort and security for the construction. As will be noted from Figs. 1 and 3, the pivot 29 is formed so as to provide an annular channel 38, for a purpose to'be described hereinafter. As will be also understood, the straps 2| and 22, the pivots 29 and 30, and the plate member 28 form a hinge means of the invention.

The forearm means l3 includes a cage member 38, preferably formed of a light material, such as an aluminum alloy, and preferably having relatively large open side windows 39 and 4D and a cut-away area 4| in the top thereof to lighten the cage as'much as possible without unduly sacrificing structural strength, to provide maximum ventllation therethrough, and to permit ilexion of the stump. As best shown in Fig. 3, the cage member 38 is provided with a relatively wide bottom portion 42 which extends the full length of the cage member and to the rearward portion of which is rigidly fixed the plate member 28 by any suitable means, such as screws 43 threaded directly into the cage member. I prefer to provide parallel rows of threaded holes 44 in the cage member to receive the screws 43 in any desired set of the holes, so as to permit slight longitudinal adjustment of the cage member relative to the plate member 28, if desired, to match the length of the forearm means |3 with the length of the normal forearm of the wearer.

Received within-the cage member 38 is a stump sheath 43 which is generally frusto-ccnical in form and is preferably formed of a light pliant material, such as leather. The stump sheath 46 is provided with a slit opening 41 in its top and with lacing eyes 48 along the sides of the opening to receive a lacing 8%, as shown in Fig. 2, to snugly secure the stump sheath 46 over the forearm stump of the wearer. The stump. sheath d''is secured to the cage member 88 only along 4 the bottom portion thereof by lacings 58 passing throu h holes 5| in the cage member and through suitable holes 52 in the stump sheath, as indicated in Fig. 2. Since the stump sheath G6 is generally frusto-conical in form, it snugly fits the end of the arm stump of the wearer and tends to evenly distribute the weight of the forearm means i3 over the entire stump, thus preventing rubbing, chafing, and general soreness caused by any concentration of pressure on any particular portion of the stump, as has been a serious difiiculty in various prior art devices.

It is also to be noted that by attaching the stump sheath E6 to the cage member 35 only along the bottom of the stump sheath and cage member, by the lacing 59, the whole weight of the forearm means L8 is carried from the bottom of the stump sheath, which effectively distributes this weight approximately uniformly over the stump, which, in addition, serves to prevent the application of excess pressures causing fatigue on any particular portion of the stump. Also, it will be noted, the cage member 38 is substantially larger in diameter than the stump sheath 46, thus permitting free circulation of air around the stump sheath to ventilate the same and permitting pronation and supination and flexion of the stump, while at the same time providing a relatively rigid metallic cage therearound to prevent injury to the stump, which is also an important object of the invention.

As best shown in Fig. 2, the outer end of the cage member 88 is provided with a threaded aperture 54 which threadedly receives an end plug 55 having a central opening 56 therein, adapted to receive a shank 51 of the tool holding means M which is adapted to be retained in any desired position relative to the forearm means l3 by a set-screw 58.

The tool holding means I4, illustrated in Figs. 1, 2, and 3, is generally of conventional form, and no claim of novelty is made thereto herein. It includes a rigid hook member 60, which is normally formed integrally with the shank 51, and a movable hook member 6| pivotally connected to the rigid hook member by a pivot pin 62, a spring 63 being provided between the hook members to normally retain the outer end of the movable hook member in engagement with that of the stationary hook member. The movable hook member BI is also provided with a projecting actuating arm 64 through an eye 65 of which is tied an actuating cord 66. The actuating cord 66 passes through the annular channel 36 of the pivot 29, passing around the lower surface thereof, and the other end of the actuating cord is adapted to be secured to a suitable shoulder strap (not shown), as is well known in the art, to permit the wearer to exert a pull through the actuating cord on the actuating arm 64 by flexing his shoulder, as is well known in the art. While there is nothing broadly new in the art in the provision of such an actuating cord, to be actuated by the shoulder of the wearer, it is novel, I believe, and a feature of my invention, to pass the cord through the guide channel 36, which forms a guide means of the invention, the channel being disposed on the axis of an imaginary line drawn through the normal epicondyles of the wearer, by reason of the design of the hinge means comprised of the pivots 29 and 38, the plate member 28, and the straps 2| and 22. This feature is important because any pull exerted by the shoulder of the wearer on the end of the actuating cord 66 is exertedsubstantially parallel to the bones of the wearers forearm, and thus there is substantially no force moment de-' veloped tending to rotate the forearm means l3 relative to the upper-arm means l2 in response to tension exerted on the actuating cord 66.

An alternative form of tool holding means is illustrated in Figs. 4, 5, 6, and '7, and contains, I believe, a number of novel and highly desirable features. The tool holding means 68 includes a circular base plate 69 from which depends a shank 10 adapted to be received in the central opening 56 of the forearm means I3, best illustrated in Fig. 2. Adjacent its lower end,-the shank I is provided with an annular groove 1| with which communicate radial holes 12, into which the inner end of the set-screw 58 is adapted to lock to retain the tool holding means 68 in either of several possible positions relative to the forearm means I3. The shank H1 is provided with a central bore 13 therethrough, which is primarily designed to lighten the construction and may be omitted if desired. The upper surface of the base plate 69, around the central bore 13, is provided with an annular semispherical shoulder 14 upon which is supported a centrally and upwardly bowed portion 15 of a centering plate 16, the centering plate being provided with a central opening 11 axially aligned with the central bore 13. The centering plate H is 'provided with a peripheral flange 19 which snugly engages the side wall 8|] of a cap member 8| The cap member 8| is provided with an annular flange 82, secured to the circular base plate 69 by screws 83, and having a depending annular rim 84. The cap member 8| has a semispherical top portion 86 provided with a central opening 81 at the top thereof from which radiate radial slots 88, as best shown in Fig. 5. Also as shown in Fig, 5, the annular flange 82 is provided with diametrically opposed open guide holes 89, for a purpose to be described hereinafter.

The tool holding means 68 also includes a chuck 90 having a shank or stem 9! extending through the central opening 81 of the cap member 8|. The top of the chuck 90 is provided with a bevelled internal shoulder 93 which is engaged by mating shoulders 94 formed on fingers 95 of a collet 96 received in the chuck. The chuck is provided with external threads 91 on which is threaded a knurled collar 98 having an internal tapered shoulder 99 adapted to engage bevelled shoulders I90 formed on the fingers 95 of the collet 96, so that when the knurled collar 98 is screwed down against the collet, the fingers of the latter are moved inwardly to grip against a tool shank held in the collet, as is well known in the art.

The upper portion of the stem 9| is provided with external threads |i|2 on which is threaded a locking ring I03 provided with a semispherical cavity I94 adapted to mate with the semispherical top portion 86 of the cap member 8|. By rotating the locking ring I03 downwardly into engagement with the top portion 86 of the cap member 8|, the stem 9| is locked in position relative to the cap member. The stem 9|, immediately below the external threads 32, is provided with a hexagonal portion I95 designed so that it will slip readily into any one of the radial slots 88 formed in the top portion 38 of the cap member 8|. Due to the hexagonal form of the portion I05 of the stem 9 I, the stem, when slipped into one of the radial slots 88. is held against rotary movement relative to the cap member 8|, andthis is a particular feature of the invention.

Formed on the stem 9| just portion I05 is an annular flange "16 adapted to engage a disk element I01 which is annular in form and into which is threaded a lower threaded end I08 of the stem 9|. A set-screw N19 is provided to lock the stem 9! relative to the disk element I81. As will be noted, the periphery of the disk element |ll'| slidably engages the inner wall of the semispherical top portion of the cap member 8%. On the lower end of the disk member ID? is provided a tubular extension H0 which receives a slidable detent element I having its lower end semispherical in form and adapted to fit into the central opening H in the centering plate 16. A compression spring H2 is provided in the tubular extension H8 and exerts force tending to move apart the detent element and the disk element I91 so as to tend to hold the detent element in the central opening 71 and to hold the disk element I9! in engagement with the semispherical top 88 of the cap member 8|.

In Fig. 7, the tool holding means 68 is shown in one of its adjusted positions. To adjust the tool holding means 68 from the position illustrated in Fig. 4, which is the centralized position, to the operating position illustrated in Fig. '7, the locking ring I03 is first slightly unscrewed to-free it from tight engagement with the semispherical to portion 86 of the cap member 8|. By exerting a lat-' eral force against the knurled collar 98 or the lOcking ring "33, the slidable detent element I is forced upwardly into the tubular extension 0 against the action of the compression spring I i2 to permit the hexagonal portion I85 of the stem 9! to pass into one of the radial slots 88 to the position illustrated in Fig. 7. As illustrated in Fig. 7, the compression spring I ll then moves the detent element outwardly onto the upper surface of the bowed portion 15 of the centering plate 16, the disk element I91 maintaining its peripheral engagement with the inner wall of the top portion 88 of the cap member 8! throughout this'movement. The locking ring 588 may then be screwed down securely into engagement With the top portion 86 of the cap member 8| to lock the stem 9| and associated mechanism sestem 9! and the shank 78 of the circular-base plate 59 so as to axially align with the forearm means I3 the collet 96 and any tool or accessory that may be held thereby. Such an accessory is illustrated in Fig. 10, which shows a fork E3 having a handle member H4 adapted to fit into, the collet 96 and to be in Fig. 7.

The tool holding means 68 is also designed to receive and secure a U-shaped accessory |||.i,-as illustrated in Figs. 6, 8, and 9. The U-shaped accessory H6 comprises a first U-shaped plate ill and a second U-shaped plate H8 secured thereto by means of a bolt H9 having a nut-|29 thereon. By loosening the nut I29, the first: and

sired rotational position the'rebetween, the same.

being fixed in the desired. position by means of the bolt andanut. The first U-shaped plate I'll.

below the hexagonal held therein, as illustrated 7 has an upper leg I2I having a relatively narrow slot I22, its inner end preferably being semicircular in form, and the plate is provided with a lower leg I23 having a relatively wide slot I24 therein, the inner end of which is also preferably semi-circular and is concentric with the inner end of the slot I22. Secured on the lower face of the lower leg I23 is a pair of pin members I25 which are adapted to fit into the guide holes 89 formed in the upper surface of the annular flange 82 of the cap member 8!, as indicated in dotted lines in Fig. 6. As will be understood from Fig. 6, the semicircular portion I21 of the wide slot I24 snugly engages the side wall 80 of the cap member ill, and the semicircular portion I26 of therelatively narrow slot I22 fits around the external threads I (32 on the stem 9!. Thus, the guide holes 89 and the pin members I25 center the U-shaped accessory H6 relative to the tool holding means 68, and by screwing the knurled collar 98 downwardly against the collet 96, the accessory i It is retained rigidly relative to the tool holding means. The accessory I I6 is of particular use in driving a car, since the second U- shaped plate H8 may be conveniently fitted around the steering wheel of a car to assist in the driving operation. As will also be apparent,

the accessory II6 may be used in conjunction with an accessory such as the fork H3 held in the collet 96, if desired, or may be separately used.

From the foregoing it will be understood that my invention includes an artificial arm of novel practical design, together with suitable acces sories and actuating mechanism therefor. The invention has been particularly developed to provide to a wearer, who has lost a hand, a mechanical device that will serve the wearer as a substitute hand or tool holding device, thus allowing him to use his past skill and training and giving him the opportunity to again be self-supporting and independent. Due to its flexibility and adaptability, my invention provides prosthesis in a marked degree,

Although I have described and illustrated a preferred embodiment of my invention, it will be understood that numerous modifications thereof may be made without departing from the spirit of my invention, and consequently I do not intend to be limited to the specific embodiments disclosed, but desire to be afforded the full protection of the following claims.

I claim as my invention:

1. In an artificial arm, the combination of. an upper-arm band adapted to be secured on the upper arm of a wearer; a forearm cage adapted to fit over a forearm stump; and hinge means connecting said band and said cage and permitting fiexure therebetween, said hinge means having a bottom portion secured to the under side of said cage and having a pair of arms projecting rearwardly from said portion into the plane of the normal epicondyles and projecting upwardly therein to pivotal points axially aligned with said epicondyles, each of said arms having pivot means at said points and having a rigid strap pivoted on said pivot means and secured to said upper-arm band.

2. In an artificial arm, the combination of: an upper-arm band adapted to be secured on the upper arm of a wearer; a forearm cage adapted to fit over a forearm stump; and hinge means connecting said band and said cage and permitting fiexure therebetween, said hinge means hav-' ing a bottom portion secured to the .under side of said cage and having a'pair of arms projecting rearwardly from said portion into the plane of the normal epicondyles and projecting upwardly and outwardly therein to pivotal points axially aligned with said epicondyles, each of said arms having pivot means at said points and having a rigid strap pivoted on said pivot means and secured to said upper-arm band.

3. In a tool holder for use on an artificial limb, the combination of: a base member having a semi-spherical top provided with a central aperture and a plurality of radial slots communicating with said aperture; a chuck having a shank extending into said top through said aperture and adapted to slide into any desired one of said slots; means for securing a tool in said chuck; and means for securing said shank relative to said top in any one of a plurality of positions.

4. In a tool holder for use on an artificial limb, the combination of: a base member having a semi-spherical top; a chuck having a shank extending into said top, a portion of said shank exterior to said top being threaded; means for preventing said shank from moving out of said top; means for securing a tool in said chuck; and a locking ring threaded on said portion of said shank and adapted to engage said top when screwed downwardly on said shank to lock said shank in any one of a plurality of positions relative to said top,

5. In a tool holder for use on an artificial limb, the combination of: a base member having a semi-spherical top; a chuck having a shank extending into said top; means for securing a tool in said chuck; means for securing said shank rel ative to said top in any one of a plurality of positions; and readily releasable means for axially aligning said shank with said top.

6. In a tool holder for use on an artificial limb, the combination of: a base member provided with an opening therein and having a semi-spherical top; a chuck having a shank extending into said top; means for securing a tool in said chuck; means for securing said shank relative to said top in any one of a plurality of positions; and readily releasable means for axially aligning said shank with said top, including a spring held detent engageable in the opening in said base member.

7. In a tool holder for use on an artificial limb, the combination of: a base member having a semi-spherical hollow top; a chuck having a shank extending into said top; a disk element on said shank in said top, the periphery of said disk element being engageable with the inner semispherical Wall of said top; means for securing a tool in said chuck; and means associated with said shank outside of said top for locking said shank in any one of a plurality of positions relative to said top.

8; In a device of the character described, the combination of: a base member having a semispherical top and an annular flange about the bottom of said top, said flange having a guide opening therein; a chuck having a shank extending into said top; retaining means for securing a tool in said chuck; a locking ring threaded on said shank and adapted to engage said top to lock said shank in any one of a plurality of positions relative to said top; and an accessory having a lower le provided with a pin adapted to fit in said guide opening and having an upper leg adapted to engage the upper surface of said locking ring, said retaining means being engageable with said upper leg to rigidly clamp said 9 accessory relative to said base member and said locking ring.

9. In a device of the character described, the combination of: a base member having a semispherical top and an annular flange about the bottom of said top, said flange havin a pair of guide openings diametrically disposed in the upper face thereof; a chuck having a shank extending into said top; retaining means for securing a tool in said chuck; a locking ring threaded on said shank and adapted to engage said top to lock said shank in any one of a plurality of positions relative to said top; and an accessory having a substantially U-shaped member provided with a pair of lower legs which are adapted to straddle said top and engage said flange, each of said lower legs having a downwardly extending pin therein adapted to fit into one of said guide openings, said U-shaped member having a pair of upper legs adapted to straddle said shank and engage said lockin ring, said retaining means being engageable with said upper legs to rigidly clamp said accessory relative to said base member and said locking ring.

10. In a tool holder for use on an artificial limb, the combination of a base member having a semi-spherical top provided with a central aperture and a plurality of radial slots communicating with said aperture; a shank extending into said top through said aperture and adapted to slide into any one of said slots; and means for securing said shank relative to said top in any one of a plurality of positions.

11. In a tool holder for use on an artificial limb, the combination of: a base member provided with a central aperture and a radial slot communicating with said aperture; a shank extending into said base member through said aperture and adapted to slide in said slot; and means for securing said shank relative to said base member in any one of a plurality of p s tio s.

KARL C. VESPER.

REFERENCES CITED The following references are 01 record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Artificial Limbs and Amputation Stumps, E. Muirhead Little, copyright 1922. (Copy available Div. page 155. 

